Integrating the differential equation of a Bouc-Wen model of hysteresis is very easy using Mathematica. In Mathematica 9, some additional checks prevent NDSolve[ ] from integrating the equation; the error message is NDSolve::smpf: Failure to project onto the discontinuity surface when computing Filippov continuation at time 0.  We can create a version-aware code to take into account this; if the Mathematica version is greater than 8, then remove DiscontinuityProcessing method.